[Functions of Smad and its binding proteins in TGF beta signal pathway].

Members of transforming growth factor-beta(TGF beta) superfamily play an important roles in regulating cell growth, differentiation and tissue homeostasis. The multi-functional roles of TGF beta are performed by phosphorylating their downstream factor Smad. It has been recently reported that Smad can physically associate with different cytosolic protein factors,such as transcription factors, coactivators and corepressors. In the TGF beta signal transduction pathways, the activated Smad directively interact with those factors to form different Smad/factors complexes which are then translocated from cytoplasm to nucleus where they regulate different TGF beta responsive gene expression for its mutifunctional roles in cells.